Here we can see the operation of the board. Every three version requires Atmel ICE for UPDI binary uploading. But by googling by the word "UPDI", I've found several implementation by various ways (one of them are on Arduino sketch, Mega328P is working as a converter from serial to UPDI !, great). I thought, the forthcoming next Arduino will be implemented by the same way as conventional Mega328P (like DTR-RST connection through capacitor), but I can add one prediction, 32U4 or something with USB and it may talk with 4809 via UPDI...

By the way, I have a naive question

Why Microchip still release new chip by "Atmel" logo? Atmel logo will remain?